The present invention concerns the assembly of pneumatic modules in a block, such as for example distribution modules.
It is known in the field of the controlled supply of pneumatic actuators (jacks, motors etc) how to use controlled distributors interposed between a common pressurised fluid supply pipe, a common exhaust collection pipe and the actuators, these distributors being grouped together in a block of juxtaposed modules, each module comprising a base through which the common pipes pass and surmounted by a distributor associated with a control solenoid valve.
In each base, there therefore exists at least one length of the common pipes which extends between flat opposite faces of the base by means of which it is associated with the bases of the adjacent modules with, between each of them, sealing elements. The holding of a block of modules as a single unit is generally provided by assembly tie rods (two tie rods) which pass through the bases perpendicular to their association faces as well as through at least one end module providing in particular the function of connection of the block to the surrounding pneumatic system.
The drawback of these assembly tie rods lies in the need to adjust their length to that of the block to be formed which, by definition, is variable since it is a function of the number of modules which it contains, a module also being able to take several dimensions in the direction of these assembly tie rods.
In addition, the advantage of the blocks of this type is an ability to be quickly modified in order to adapt the installation to the requirements of the actuators used and to the change in the installation over time. However, modifying the configuration of the block requires dismantling it and therefore withdrawing the two tie rods and refitting others adapted to the new dimension of the modified block. This is a handicap impairing the flexible and adaptable character of this type of installation.
By means of the present invention it is possible to improve the ability to be modified of a block by virtue of means of connecting the bases to each other which are independent of the number and thickness of the bases. In addition these connection means are reduced to a single tightening line, which releases an internal volume in the base which can be used for other purposes such as, all other things being equal, an increase in the cross-sections of the internal channels.
Thus, for this purpose, the object of the invention is a block of pneumatic modules including a plurality of adjacent distribution modules, juxtaposed and kept tightened against each other along parallel faces and between two end modules by connection means passing through all the distribution modules and at least one of the end modules, in which the assembly means comprise, for each distribution module, a single through rod with a first externally threaded end and a second internally threaded end and means for rotationally keying and unkeying each rod with respect to the module which it passes through.
The invention therefore proposes to use only one assembly tie rod which consists of a succession of rods screwed to each other end to end so that it is possible to associate with each module a rod with an appropriate length which is removed from the assembly means or which is added thereto depending on whether a module is being removed or added.
Naturally the block has, on the side of one of its end elements, a sort of nut keyed in this block in order to receive the end of the modular tie rod whilst the other end module of the block has passing through it a rod according to the invention which is provided with a tightening head and which makes it possible to keep all the modules in the block held against each other by tightening. It will be understood that, when a block is disconnected by acting on the head of the above mentioned rod passing through the second end module of the block, there is uncertainty with regard to the prediction of the threaded connection which will break open first. This is because, in such a succession of threaded assemblies of the rods end to end, the separation of one rod with respect to another will take place at the point where the assembly is least capable of transmitting a loosening torque. To mitigate this drawback provision has been made according to the invention for each rod associated with a distribution module of the block to have means, once in place, making it possible to key it rotationally with respect to the distribution block which it passes through. Preferably these means will consist of a head whose external shape is not of revolution about the axis of the rod provided at the internally threaded end of the rod which, when it is in place, projects outside an association face of a module, so as to be received by a recess provided in the association face of the adjacent module with a shape corresponding to the external shape of the head so as to key the rod with respect to this recess by correspondence of shapes.